Japan is considering prioritising its Olympic athletes for coronavirus vaccines, aiming to get them innoculated before the pandemic-postponed Tokyo Games open on July 23, local media said Thursday.

Japan's government denied any such plan was being considered, but said it would be "closely watching discussions" about protecting athletes' health.

The reported move sparked criticism online, with one Japanese Twitter user demanding: "Give it to my granny first!"

Japan's vaccine rollout is moving slowly, with just one million first doses given so far to medical workers since jabs began in February.

Older people will start receiving doses only from next week, and so far Japan has approved only the Pfizer vaccine.

A date has not yet been set for vaccinating the broader population, but the government is now considering giving Japanese athletes both shots by late June, Kyodo News agency reported, citing unnamed government sources.

Private broadcaster Nippon TV and other media also reported the plan, with some pointing out that the proposed timeline would mean healthy young athletes would finish their inoculations before some of Japan's elderly.

Top government spokesman Katsunobu Kato said there was "no fact in the claim that the government is studying such a plan and the government has no intention of discussing it at this point."

But he told reporters the government would be "closely watching discussions on athletes' health issues" among Olympic officials, the Tokyo Games organisers and host city Tokyo.

Online, the reports were met with criticism, with one Japanese Twitter user calling on "all the athletes to come out and say they won't do this."

-Will you thank the old and sick people who died because their vaccines were late for giving their lives for the Olympics?- asked another.

Japan has seen a comparatively small virus outbreak, with just over 9,200 deaths since the pandemic began.

But infections have spiked recently in several parts of the country, including Osaka in western Japan, which has decided to bar the Olympic torch relay from public roads in the prefecture.

Polling shows a majority of Japanese want to see the Games cancelled or postponed further, though support for holding it this year has increased slightly, hovering below 30 percent.

IOC President Thomas Bach has said vaccination is not a requirement for athletes competing at the Tokyo Games, but that Olympic officials will encourage participants to get the jab.

The IOC plans to offer vaccines secured from China to athletes in countries without access.